function Bomb(){
    this.start=function(){
        setTimeout(()=>{
            console.log("Bomb!");
        },3000)
    }
    this.clear=function(){
        console.log("Clear Bomb!")
    }
}
var b1=new Bomb();
var b2=new Bomb();
b1.start();
b2.start();
setTimeout(()=>{
    b2.clear();
},4000)